<template>
  <div class="cartcontrol">
    <!-- 根据食物数量food.count是否需要显示减号 -->
    <transition name="move">
      <div class="cart-decrease" v-show="food.count>0" @click.stop.prevent="decreaseCart">
        <span class="inner icon-remove_circle_outline"></span>
      </div>
    </transition>
    <!-- 是否显示数量 -->
    <div class="cart-count" v-show="food.count>0">{{food.count}}</div>
    <div class="cart-add icon-add_circle" @click.stop.prevent="add"></div>
  </div>
</template>

<script type="text/ecmascript-6">
  export default {
    props: {
      food: {
        type: Object
      } 
    },
    methods: {
      add(event) {
        if (!this.food.count) {
          //响应式添加属性
          this.$set(this.food, 'count', 1);
        } else {
          this.food.count++;
        }
        //将事件发送出去，同时获取点击元素，event.target 获取点击元素
        //可以理解为调用父组件中方法的一种方式
        this.$emit('add', event.target);
      },
      decreaseCart() {
        if (this.food.count) {
          this.food.count--;
        }
      }
    }
  };
</script>

<style lang="stylus" rel="stylesheet/stylus">
  .cartcontrol
    font-size: 0
    .cart-decrease
      display: inline-block
      padding: 6px
      opacity: 1
      transform: translate3d(0, 0, 0)
      .inner
        display: inline-block
        line-height: 24px
        font-size: 24px
        color: rgb(0, 160, 220)
        transition: all 0.4s linear
        transform: rotate(0)
      &.move-enter-active, &.move-leave-active
        transition: all 0.4s linear
      &.move-enter, &.move-leave-active
        opacity: 0
        transform: translate3d(24px, 0, 0)
        .inner
          transform: rotate(180deg)
    .cart-count
      display: inline-block
      vertical-align: top
      width: 12px
      padding-top: 6px
      line-height: 24px
      text-align: center
      font-size: 10px
      color: rgb(147, 153, 159)
    .cart-add
      display: inline-block
      padding: 6px
      line-height: 24px
      font-size: 24px
      color: rgb(0, 160, 220)
</style>